1. Technical Field
The present invention relates to a label sheet.
2. Related Art
Label sheets are used for the usage of a wide range such as commercial use, business use or home use as labels, seals, stickers, emblems etc. There are various kinds of label sheets such as printing label sheets, label sheets for an inkjet printer, label sheets for an image forming apparatus of an electrophotography type such as label sheets for a laser printer. These various kinds of label sheets are respectively subjected to desired kinds of printings in accordance with the usages thereof and used. In general, each of these label sheets is configured by a label base material, a release liner and an adhesive layer formed between the label base material and the release liner, and is used in a manner, for example, that, after the desired printing is performed on the label base material by-the corresponding one of the various kinds of printings, the label base material is exfoliated from the release liner between the release liner and the adhesive layer and then the label base material is pasted on a subject to be pasted and is used.
Meanwhile, it is quite important to prevent forgery in a special document such as a paper money or a security. In order to prevent the forgery of such the special documents, the technique has been known in which metal fiber such as magnetic material detectable by a magnetic device is laid or buried within the special document.
Further, in recent years, due to the spread of computers and networks, it has become possible to easily extract information among enormous information and print and copy the extracted information. Thus, such a problem has been brought into the public eye that printed documents obtained by illegally printing or copying high security information are taken out and so secret information is leaked. Therefore, in order to prevent the leakage of secret information caused by that printed documents obtained by illegally printing or copying high security information are taken out, various kinds of apparatuses and methods have been proposed in which security as to information is enhanced.
For example, there has been known a method in which metal fiber such as magnetic material having large Barkhausen effect is contained within a sheet and a detecting device detects a pulse signal caused by the magnetic material by utilizing the large Barkhausen effect of the magnetic material to thereby confirm the presence of the sheet.